North of Nakatsu, the line runs above ground in the median of the Shin-Midosuji expressway. It only returns underground when it arrives at Senri-Chuo.

On maps, the Midosuji is red. Its trains use a third rail, and come in three types: the older Type 10, newer Type 21, and disgustingly old Polestar 8000 (the latter of which is used by Kita Osaka Kyuko, and is instantly recognizable by its cream-colored plasticky exterior).